9404_WashingtonCo_techreviewletter_DIN27661_20170419

From:Ritter, Christine
To:"[e-mail]"
Cc:Madeline German ([e-mail]); Joan Smyth ([e-mail]); Chao, Ming-tai;
Lane, Ervin
Subject:Washington County 9404-CDLF and 9402-MSWLF
Date:Wednesday, April 19, 2017 12:23:00 PM
Attachments:image001.png
DIN 27661

Mr. Critcher:

Following are my comments on the Water Quality Monitoring Plan (WQMP) and Landfill Gas
Monitoring Plan (LFGMP), DIN 27659, submitted for the following landfill facilities:
Washington County 9404-CDLF and 9402-MSWLF.

The WQMP and LFGMP submitted as part of the Permit to Operate application for continued
operations at the CDLF combines two adjacent landfill facilities, an active unlined C&DLF
(9404-CDLF) and a closed unlined MSWLF (9402-MSWLF). By combining monitoring activities
at the two adjacent units, the monitoring activities at both facilities will be regulated under
Solid Waste Rule requirements for active C&DLFs, 15A NCAC 13B .0544 Monitoring Plans
and Requirements for C&DLF Facilities. Additionally, as there are 2L exceedances in the
groundwater at both landfill facilities, 15A NCAC 13B .0545 Assessment and Corrective
Action Program for CDLF Facilities and Units will also be applicable.

Please include a potentiometric surface map for the entire area of the combined landfill
facilities. Please superimpose the potentiometric surface map over a topographic map, as
opposed to an aerial photograph, to better distinguish monitoring well locations from the
surrounding environment and to better correlate topographic features and groundwater
flow. Please include pertinent features as wetlands, streams, ponds, ditches, property
boundaries, etc.

There have been Groundwater Protection (GWP) and 2L exceedances of both organic and
inorganic constituents detected in the groundwater at both landfill facilities for at least the
previous 3 groundwater sampling events including September 2015, March 2016, and
September 2016. A letter from Ervin Lane, compliance hydrogeologist with the NC Solid
Waste Section, is forthcoming and will request additional investigation, assessment, and/or an
Alternate Source Demonstration (ASD) submittal for both facilities. As a result of the current
groundwater exceedances at both facilities, detection monitoring is not sufficient at the two
facilities. The current groundwater monitoring well network is not adequately monitoring
contamination occurring at the closed MSWLF or at the active CDLF. Groundwater
exceedances have been detected consistently at MW-2 and CD-1, CD-2, and CD-3, all
downgradient wells. Additional well locations will better define the extent of groundwater
contamination.

Please submit a figure depicting methane monitoring locations superimposed on a
topographic map. The NC Solid Waste Section agrees that due to the shallow groundwater
conditions of generally 3 feet or less at both facilities that permanent landfill gas monitoring
wells are not practical. Please consider and discuss the potential option of using the bar hole
punch method for sampling of landfill gas at the two facilities.

Please contact me if you have any questions.

Thank you,

Christine Ritter
Hydrogeologist
Solid Waste Section
Division of Waste Management
NC Dept of Environmental Quality

919 707 8254 office
[e-mail]

Mailing address:
1646 Mail Service Center
Raleigh, North Carolina 27699-1646

Physical address:
217 West Jones Street
Raleigh, NC 27603

Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.